1. Field of the Invention
The present invention relates to an azeotropic mixture consisting essentially of hydrogen fluoride (hereinafter, referred to as xe2x80x9cHFxe2x80x9d) and dichloromethane (hereinafter, referred to as xe2x80x9cR-30xe2x80x9d), an azeotropic mixture consisting essentially of HF and chlorofluoromethane (hereinafter, referred to as xe2x80x9cR-31xe2x80x9d) and an azeotropic mixture consisting essentially of HF and difluoromethane (hereinafter, referred to as xe2x80x9cR-32xe2x80x9d), and a process for the removal of HF from a mixture comprising HF and R-30, R-31 and/or R-32.
R-32 is focused on as a substitute cooling medium for chlorodifluoromethane, and R-30 and R-31 are starting materials for the production of R-32.
2. Description of the Related Art
R-30, R-31 and/or R-32 are conventionally produced by reacting a chlorinated hydrocarbon such as R-30 with HF. Hitherto, a process has been employed in which HF is removed by washing the mixture produced by the reaction and unreacted materials comprising HF, R-30, R-31 and R-32 with an aqueous phase. This process is not so effective because an large amount of an alkali is required to neutralize the washing aqueous solution, and also because a waste from the neutralization has to be treated.
The present invention provides a process to concentrate or remove HF or other components by forming an azeotropic mixture of HF and R-30, R-31 or R-32 and optionally utilizing liquid separation of a mixture of HF and R-30 and/or a mixture of HF and R-31 into an upper liquid phase and a lower liquid phase under certain conditions.